The present invention relates to 2,2,6-trimethyl-1-cyclohexene-1-ylacetaldehyde (or "beta-cyclohomocitral") produced by, interalia, a novel process described and claimed in copending Applications for U.S. Letters Pat. No. 507,414, filed on Sept. 19, 1974 (now U.S. Pat. No. 3,956,393, issued on May 11, 1976), and U.S. Pat. No. 594,100, filed on July 8, 1975 (now U.S. Pat. No. 3,980,708, issued on Sept. 14, 1976) and novel compositions using such beta-cyclohomocitral to alter, modify, enhance the aroma of a perfumed composition or a perfumed article or enhance the aroma of a perfumed composition or perfumed article.
There has been considerable work performed relating to substances which can be used to impart, modify, alter or enhance fragrances to (or in) various consumable materials such as perfumed compositions and perfumed articles such as soaps, colognes and detergents. These substances are used to diminish the use of natural materials, some of which may be in short supply and/or to provide more uniform properties in the finished product. Woody, camphoraceous, green, rosey, floral and earthy notes are desirable in several types of perfumed compositions and perfumed articles.
Arctander, "Perfume and Flavor Chemicals," 1969 discloses the use in perfume compositions and flavors of "cyclocitral," "dehydro-beta-cyclocitral," "isocyclocitral," "alpha-cyclocitrylidene acetaldehyde" and "beta cyclotrylidene acetaldehyde," thus:
i. ""760" CYCLOCITRAL Alpha-cyclocitral = (2,2,6-trimethyl-5-cyclohexen-1-carboxaldehyde). beta-cyclocitral = (2,2,6-trimethyl-6-cyclohexen-1-carboxaldehyde). Both isomers are known and have been produced separately. ##STR5## Very rarely offered commercially. These particular cyclocitrals have little or no interest to the creative perfumer, but they have served as part of many pieces of proof that isomers (alpha-beta) do often have different odors." PA1 ii. "761: iso-CYCLOCITRAL A mixture of two chemicals: 3,5,6-trimethyl-3-cyclohexen-1-carboxaldehyde (meta-cyclocitral). ##STR6## 2,4,6-trimethyl-4-cyclohexen-1-carboxaldehyde (symmetric-iso-cyclocitral). ##STR7## Powerful, and diffusive, foliage-green, "dark" weedy and dry odor, sometimes described as "Flower-shop odor." The earthy and wet-green notes are quite natural in high dilution and resemble the odor of stems from plants and flowers fresh from the soil. PA1 Finds use in perfume compositions where it blends excellently with Oakmoss products (compensates from sweetness and lifts the topnote), with Inonoes (freshness), Geranium "vegetable" notes), etc. ...." PA1 iii. "762: alpha CYCLOCITRYLIDENE ACETALDEHYDE ##STR8## Mild, floral-woody, somewhat oily-herbaceous odor, remotely reminiscent of Rose with similarity to the odor of hydrogenated Ionones. PA1 Suggested for use in perfume compositions. It brings a certain amount of floral lift to Rose compositions, and performs fairly well even in soap. However, the cost of the rarely offered and never readily available lots are rather discouraging to the perfumer, and it is most conceivable that this material can be left out of the perfumer's library without any great loss. ..." PA1 iv. "763: beta-CYCLOCITRYLIDENE ACETALDEHYDE 2,6,6-trimethyl-1-cyclohexenyl-beta-acrolein. ##STR9## Sweet-woody, rather heavy odor, resembling that of beta-Ionone. More fruity than really floral, but not as tenacious as the Ionone. Suggested for use in perfume compositions, but since it does not offer any new or unusual odor characteristics, and it cannot be produced in economical competition to beta-Ionone, there is little or no chance that it will ever become a standard shelf ingredient for the perfumer. ..." PA1 v. "869: DEHYDRO-beta-CYCLOCITRAL (Safranal) 2,6,6-trimethyl-4,4-cyclohexadiene-1-carboxaldehyde ##STR10## Very powerful, sweet, green-floral and somewhat tobacco-herbaceous odor of good tenacity. In extreme dilution reminiscent of the odor of Safran (Saffron). PA1 Interesting material for fresh topnotes, as a modifier for aldehydic-citrusy notes, as a green-floral topnote in flower fragrances, etc. It blends excellently with the aliphatic Aldehydes, with Oakmoss products and herbaceous oils. ..." PA1 i. Reacting beta-ionone having the formula: ##STR12## in the absence of dimethyl formamide with a peralkanoic acid having the formula: ##STR13## (wherein R is hydrogen, methyl or ethyl) to form beta-ionone enol ester having the formula: ##STR14## and not the expected beta-ionone epoxide having one of the formulae: ##STR15## ii. hydrolyzing the beta-ionone enol ester in the presence of base (aqueous or alcoholic) to form beta-cyclohomocitral. PA1 i. The reaction is preferably carried out at temperatures of from 15.degree. C up to about 75.degree. C. Lower temperatures result in slower and less complete reaction and higher temperatures than 75.degree. C result in lower yields of the desired product and significantly higher percentages of by-products. The most preferred temperature of reaction is 25.degree. C. PA1 ii. A slight molar excess (from 10 up to 15 percent) of peracetic acid gives a slightly higher yield of product. A large excess (about 200 percent), however, results in the formation of dihydroactinodiolide having the structure: ##STR16## in about 30-35 percent yield when no buffer (e.g., potassium acetate) is present in the reaction mass; PA1 iii. Where potassium carbonate is substituted for potassium acetate as a buffer, the yield of product obtained is substantially the same; PA1 iv. On the other hand, a slightly lower yield of product is obtained by substituting sodium acetate for potassium acetate as the buffer; PA1 v. Substitution of formic acid for acetic acid in the reaction mass gives rise to a lower yield of product; PA1 vi. Any solvent inert to the action of peralkanoic acids may be used in this first oxidation reaction using alkanoic acids. For instance, the use of cyclohexane or chloroform as a solvent does not have an appreciable effect on the yield of product; PA1 vii. Omission of the buffer (i.e., thus performing the reaction under strongly acidic conditions) results in an incomplete reaction, lower yield and greater quantity of by-product(s); PA1 viii. The use of dimethyl formamide as solvent results in the exclusive formation of beta-ionone epoxide having the structure: ##STR17## in about 70-75% yield and, accordingly, the presence of dimethyl formamide must be avoided; PA1 ix. The use of monoperphthalic acid (performed in situ) from phthalic anhydride and hydrogen peroxide) yields beta-ionone epoxide in 60-70 percent yield. The use of perbenzoic acid in place of a peralkanoic acid has also been used to make beta-ionone epoxide R. Yves, et al., Helv. Chim. Acta, 29, 880 (1946).
Safranal and beta-cyclocitral are disclosed as volatile constituents of Greek Tobacco by Kimland et al,. Phytochemistry 11 (309) 1972. Beta-cyclocitral is disclosed as a component of Burley Tobacco flavor by Demole and Berthet, Helv. Chim. Acta. 55 Fasc-6, 1866 (1972).